Première réunion de la ligue des nations à Londres, Albert Thomas et M. [Léon] Bourgeois au Palais St James : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 57999

Impaired fast-spiking, suppressed cortical inhibition and increased susceptibility to seizures in mice lacking Kv3.2 K+ channel proteins

Voltage-gated K+ channels of the Kv3 subfamily have unusual electrophysiological properties, including activation at very depolarized voltages (positive to −10 mV) and very fast deactivation rates, suggesting special roles in neuronal excitability. In the brain, Kv3 channels are prominently expressed in select neuronal populations, which include fast-spiking (FS) GABAergic interneurons of the neocortex, hippocampus, and caudate, as well as other high-frequency firing neurons. Although evidence points to a key role in high-frequency firing, a definitive understanding of the function of these channels has been hampered by a lack of selective pharmacological tools. We therefore generated mouse lines in which one of the Kv3 genes, Kv3.2, was disrupted by gene-targeting methods. Whole-cell electrophysiological recording showed that the ability to fire spikes at high frequencies was impaired in immunocytochemically identified FS interneurons of deep cortical layers (5-6) in which Kv3.2 proteins are normally prominent. No such impairment was found for FS neurons of superficial layers (2-4) in which Kv3.2 proteins are normally only weakly expressed. These data directly support the hypothesis that Kv3 channels are necessary for high-frequency firing. Moreover, we found that Kv3.2 −/− mice showed specific alterations in their cortical EEG patterns and an increased susceptibility to epileptic seizures consistent with an impairment of cortical inhibitory mechanisms. This implies that, rather than producing hyperexcitability of the inhibitory interneurons, Kv3.2 channel elimination suppresses their activity. These data suggest that normal cortical operations depend on the ability of inhibitory interneurons to generate high-frequency firing.

GENCODE: producing a reference annotation for ENCODE

Background: The GENCODE consortium was formed to identify and map all protein-coding genes within the ENCODE regions. This was achieved by a combination of initial manualannotation by the HAVANA team, experimental validation by the GENCODE consortium and a refinement of the annotation based on these experimental results.Results: The GENCODE gene features are divided into eight different categories of which onlythe first two (known and novel coding sequence) are confidently predicted to be protein-codinggenes. 5’ rapid amplification of cDNA ends (RACE) and RT-PCR were used to experimentallyverify the initial annotation. Of the 420 coding loci tested, 229 RACE products have beensequenced. They supported 5’ extensions of 30 loci and new splice variants in 50 loci. In addition,46 loci without evidence for a coding sequence were validated, consisting of 31 novel and 15putative transcripts. We assessed the comprehensiveness of the GENCODE annotation byattempting to validate all the predicted exon boundaries outside the GENCODE annotation. Outof 1,215 tested in a subset of the ENCODE regions, 14 novel exon pairs were validated, only twoof them in intergenic regions.Conclusions: In total, 487 loci, of which 434 are coding, have been annotated as part of theGENCODE reference set available from the UCSC browser. Comparison of GENCODEannotation with RefSeq and ENSEMBL show only 40% of GENCODE exons are contained withinthe two sets, which is a reflection of the high number of alternative splice forms with uniqueexons annotated. Over 50% of coding loci have been experimentally verified by 5’ RACE forEGASP and the GENCODE collaboration is continuing to refine its annotation of 1% humangenome with the aid of experimental validation.

Financiamento dos Sistema de Saude

Este Relatório sobre a Saúde no Mundo foi produzido sob a direcção geral de Carissa Etienne, Assistente do Director-Geral, Sistemas e Serviços de Saúde e Anarfi Asamoa-Baah, Director Geral Adjunto. Os redactores principais froam David B Evans, Riku Elovainio e Gary Humphreys; com contribuições de Daniel Chisholm, Joseph Kutzin, Sarah Russell, Priyanka Saksena e Ke Xu. Contribuições sob a forma de caixas de texto e análises foram fornecidos por: Ole Doetinchem, Adelio Fernandes Antunes, Justine Hsu, Chandika K. Indikadahena, Jeremy Lauer, Nathalie van de Maele, Belgacem Sabri, Hossein Salehi, Xenia Scheil-Adlung (ILO) and Karin Stenberg. Sugestões e comentários foram recebidos dos Directores Regionais, Assistentes do Director-Geral e respectivas equipas. Análises, dados e revisões da organização do texto, vários rascunhos ou secções específicas foram fornecidos por (em adição às pessoas jáacima mencionadas): Dele Abegunde, Michael Adelhardt, Hector Arreola, Guitelle Baghdadi-Sabeti, Dina Balabanova, Dorjsuren Bayarsaikhan, Peter Berman, Melanie Bertram, Michael Borowitz, Reinhard Busse, Alexandra Cameron, Guy Carrin, Andrew Cassels, Eleonora Cavagnero, John Connell, David de Ferranti, Don de Savigny, Varatharajan Durairaj, Tamás Evetovits, Josep Figueras, Emma Fitzpatrick, Julio Frenk, Daniela Fuhr, Ramiro Guerrero, Patricia Hernandez Pena, Hans V Hogerzeil, Kathleen Holloway, Melitta Jakab, Elke Jakubowski, Christopher James, Mira Johri, Matthew Jowett, Joses Kirigia, Felicia Knaul, Richard Laing, Nora Markova, Awad Mataria, Inke Mathauer, Don Matheson, Anne Mills, Eduardo Missoni, Laurent Musango, Helena Nygren-Krug, Ariel Pablos-Mendez, Anne-Marie Perucic, Claudia Pescetto, Jean Perrot, Alexander Preker, Magdalena Rathe, Dag Rekve, Ritu Sadana, Rocio Saenz, Thomas Shakespeare, Ian Smith, Peter C Smith, Alaka Singh, Ruben Suarez Berenguela, Tessa Tan-Torres Edejer, Richard Scheffler, Viroj Tangcharoensathien, Fabrizio Tediosi, Sarah Thomson, Ewout van Ginneken, Cornelis van Mosseveld e Julia Watson. A redacção do Relatório foi informada por muitos indivíduos de várias instituições que forneceram documentos de suporte; estes documentos de suporte podem ser encontrados em: http://www.who.int/healthsystems/topics/financing/healthreport/whr_background/en Michael Reid editou as cópias do Relatório, Gaël Kernen produziu as figuras e Evelyn Omukubi forneceu o valioso apoio secretarial e administrativo. O desenho e paginação foi feito por Sophie Guetaneh Aguettant e Cristina Ortiz. Ilustração por Edel Tripp (http://edeltripp.daportfolio.com). A tradução foi realizada por Jorge Cabral e Aurélio Floriano e revista por Aurélio Floriano e Paulo Ferrinho, do Instituto de Higiene e Medicina Tropical, da Universidade Nova de Lisboa - Lisboa, Portugal. A publicação foi produzida com o apoio da Comunidade dos Países de Língua Portuguesa (CPLP), sob autorização do Director Geral da Organização Mundial da Saúde (OMS). As informações contidas neste Relatório não podem, de forma alguma, ser tomadas como a expressão das posições da CPLP